Passwords are used in many situations in which authentication of a user is desired or needed. As examples, passwords are used when logging into computing systems, in using credit/debit cards, in communicating electronically, in electronic transactions, in locking/unlocking locks, etc.
There are various types of passwords, including those that are keyed-in and those that are graphical in nature. Passwords that are keyed-in are susceptible to being mistyped, and often, passwords, regardless of type, are forgotten. Passwords must also be protected.
The protection of passwords has become increasingly more difficult. Clever techniques have been created to discover a user's password. For example, key logging programs, which are difficult to detect with anti-virus programs, have been developed that capture every key stroke that is entered through a keyboard. This leaves the user's password vulnerable.
Even graphical passwords are vulnerable to screen shots and/or video display of the graphic images that have been entered.